Ethnic Discord : Uneasy Wait for Muslim Refugees : They fled Serbian concentration camps and found shelter in Croatia. But now, the Croats, too, may be their enemies.

KARLOVAC, Croatia — They were the victims of an often confusing war whose gaunt figures, bruised limbs and haunted eyes first helped the world outside Bosnia-Herzegovina understand what it meant to be "ethnically cleansed."

From Serbian concentration camps these thousands of Muslim detainees made their way to a transit camp in neighboring Croatia, where they joined more than half a million refugees from Bosnia's 14-month-old war awaiting an end to the fighting--or if the end doesn't come, a home somewhere else.

But safety and shelter, in a war whose frontiers and alliances shift like light on water, can be fleeting things. As Croats and Muslims have turned against each other on the battlefields of central Bosnia in recent weeks, the hundreds of thousands of Muslim refugees sheltered in Croatia have begun to fear again for their future in a land that now may be the home of another enemy.

As images of Muslim troops ravaging Croatian villages in Bosnia play across newspaper front pages, veiled Muslim women on the streets of Zagreb say people now often mutter "dirty Muslim" at them as they pass. A small bomb exploded at a Muslim refugee center near the southern city of Split last week, and 680 Muslim refugees launched a protest when Croatian authorities attempted to move them to a new center they feared was too close to the war zone.

"They say there are half a million Muslim refugees in Croatia. And I ask myself if our Bosnian Muslim politicians ever think of us. Because we worry what is going to happen to us," said one former inmate of the dreaded Omarska detention camp in western Bosnia. "We hang here on a string. We are standing neither on the earth nor in the sky. The world is promising things to us, and that is our only hope."

Government officials on both sides fear the situation can only get worse. More than 3,000 Croatian refugees have arrived from Bosnia in the last week, and an estimated 20,000 more displaced from their homes in the fighting--some estimates are as high as 40,000--are in the forests around Travnik and in nearby Vares and Kakanj. Croatian authorities say many will probably try to make their way toward Croatia in the coming weeks--adding more fuel to an already explosive mixture of overcrowded facilities, an increasingly wary government and a hostile public.

Some of the hostility erupted visibly last week, when thousands of Croatian refugees, newly arrived from central Bosnia, were told they were being relocated back into Bosnia-Herzegovina, in part because Muslim refugees have flooded the existing facilities in Croatia. Angry protests broke out, and about 850 of them refused to go.

"I understand the rage of our citizens, but we don't want this rage to get out of control," said Adalbert Rebic, head of the Croatian Office for Refugees. "I'll do anything in my power to try to appease the situation, and I beg my Muslim brothers to understand that we have to live together. If they don't understand this, I foresee a very sad end."

Already, hard-liners within the Croatian government have begun asking why Croatia is sheltering the wives and children of Muslim fighters who are killing Croats in neighboring Bosnia.

The fledgling nation, one of the first of the former Yugoslav republics to declare independence, has spent $1.6 billion sheltering refugees who number up to 12% of its own population. International aid has totaled only $38 million, Croatian authorities say, and Europe and the United States have been slow to welcome Bosnian refugees. So far, 595,000 have been settled abroad, leaving Croatia alone to shelter another 526,000 refugees. More than 261,000 of them are from Bosnia-Herzegovina, the rest Croats displaced from Croatian territories occupied by the Serbs.

"Croatia is exhausted. We have no more possibility to receive more refugees from Bosnia, and yet every day we are receiving 300," said Rebic, who blames Serbia for instigating the latest round of Muslim-Croat fighting.

"This is another form of war against Croatia, by economic means," he declared. "Maybe they're hoping to give us another million refugees, so Croatia just breaks down."

About three-fourths of the Bosnian refugees are Muslims, many of them housed in hotels along the scenic Adriatic coast in conditions that recently have begun to inspire envy among displaced Croats often sheltered in less comfortable circumstances.

"We cannot possibly understand how Muslims in Bosnia are attacking Croatians who are giving shelter to their families for such a long time. We cannot understand it, and we also feel that Muslim refugees have better conditions of life, much better," said Silvija Zepan, who fled from the Croatian city of Vukovar two years ago when it was destroyed by the Serbs. Now, she and 750 of her neighbors live in a barracks on the outskirts of Zagreb, waiting for the seemingly distant day when the Croats take Vukovar back.